HSE PUBLISHES UPDATED GUIDANCE ON DUST EXPLOSIONS

HSE press release E221:03 - 20 November 2003

The Health and Safety Executive (HSE) has published fully revised and updated guidance aimed at industries dealing with combustible dusts, informing them of the safest way of handling them.

Safe Handling of Combustible Dusts seeks to lower the risk of a dust explosion, present in industries such as food production (sugar, flour, custard powder), animal feed production and places handling sawdust, many organic chemicals, plastics, metal powders and coal.

The booklet is targeted at those who operate plants handling dusts which can explode. It describes in simple language the tests used on dusts to assess their explosive properties, the precautions used to control the risks and an outline of the health and safety law that applies.

Dust explosions occur when fine materials are disbursed to a certain concentration and an effective ignition source is present. If dust deposits around premises form a cloud an initial small explosion is often followed by a much larger one. Much can be done at the design stage to prevent such explosions, but some risks usually remain. There are many ongoing precautions that need to be followed by those who work in the plant. These are outlined in the booklet.

The booklet takes account of European Directive 99/92/EC on the Protection of Workers Potentially at Risk from Explosive Atmospheres (The ATEX Directive) which is implemented in the UK by the Dangerous Substances and Explosive Atmospheres Regulations. In particular, the guidance describes how the requirement for hazardous area classification, brought in by the Regulations, applies to dust handling plants, and explains which types of new equipment need to be 'ATEX compliant' ie be properly marked after undergoing specified tests and checks for their use in hazardous areas.

Alan Tyldesley, section head responsible for production of this guidance in HSE's Hazardous Installations Directorate, said: "Large dust explosions in the UK are fortunately few and far between, but the risk is present in many industries. Much research carried out over the last ten years by groups across Europe underpins this guidance, but very simple failings can still lead to a major explosion if the risks are not understood at the workplace. Earlier this year two incidents at polymer processing plants in the USA resulted in 13 fatalities and over 50 injured employees which shows the potential devastation resulting from a dust explosion".

Copies of 'Safe handling of combustible dusts: precautions against explosions' HSG103, ISBN 0 7176 2726 8, price £10.95 are available from HSE Books

Notes to editors

1. The Dangerous Substances and Explosive Atmospheres Regulations (DSEAR) (SI No. 2776/2002) introduce for the first time a requirement for hazardous area classification, and certification of some types of equipment used where there is an explosion risk.

2. Four technical approved codes of practice and guidance for the Regulations have recently been published. These are: L134 'Design of plant, equipment and workplaces'; L135 'Storage of dangerous substances'; L136 'Control and mitigation measures'; and L137 'Safe maintenance repair and cleaning procedures'. A fifth general ACOP is due to be published in December.

3. The ATEX Directive was implemented by DSEAR, which came into force on 8 December 2002. ATEX based requirements did not come into force into effect until 1 July 2003. The Directive establishes minimum requirements for the protection of workers potentially at risk from explosive atmospheres.

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